The increased use of polymers in various applications has increased the need for polymer compositions exhibiting reduced fire hazard characteristics. Recent governmental regulations have restricted the use of certain polymer materials in various areas so that the flame retardance and smoke toxicity of such materials must be considered in selecting polymers for use in particular applications.
A common method for reducing the flammability of a polymer composition comprises introducing elements into the polymer matrix which pyrolyze to form volatile gases which interfere with combustion of the polymer materials. Elements which have been introduced into polymer compositions include organo-halogens, for example, those that contain chlorine and bromine. Another method for improving the flame retardant characteristics of polymer compositions comprises adding high loadings of flame retardant filler materials such as alumina trihydrate, antimony oxide, magnesium hydroxide and the like. However, because alumina trihydrate exhibits a rather low degradation temperature, approximately 400.degree. F., its use is precluded in many polymer applications which require high processing temperatures. Additionally, organo-halogens containing chlorine and bromine have been used in combination with filler materials such as antimony oxides and/or borates to provide additional fire retarding characteristics.
Additional materials have also been added to polymer compositions to improve their flame retardant characteristics. For example, the Stratta et al U.S. Pat. No. 4,394,469 and the Ashman et al U.S. Pat. No. 4,100,075 disclose surface treated antimony compounds which may be included in various organic resin and elastomer systems to improve flame-retardant properties. The Nies et al U.S. Pat. No. 3,860,692 discloses the use of crystalline sodium aluminum borate as a fire retardant for polyester compositions while the Woycheshin et al U.S. Pat. No. 3,878,166 and Japanese Patent No. 52-29838 disclose the use of dawsonite materials as flame retardant compounds in polymer compositions. The Fielding et al U.S. Pat. No. 3,872,052 also discloses polypropylene compositions including dawsonite materials. The Keogh U.S. Pat. No. 4,353,997 discloses silane modified alkylene-alkyl acrylate copolymers including both a mineral filler and a halogenated flame retardant additive.
As the use of polymer compositions in various applications increases, the need for such compositions exhibiting improved flame retardant characteristics continues.